The Nike Air Zoom Katana Rac3r III is a lightweight, performance shoe recommended for road racing distances. Ultra light performance mesh upper with reinforced TPU welding to support the midfoot and heel. Full-length molded Phylon™ midsole with a responsive heel Zoom Air™ unit. Molded TPU shank adds midfoot rigidity and support. Heel BRS 1000™ carbon rubber in the heel and two panels of DSP injected material provide full traction at top speed. Wt. 5.6 oz.